Office



' of which the following isa specification.

' metal is liable to warp and crack in the pro- To all whom it mayconcern:

-England, have invented new and useful Imand roughly boring them, thentempering or length, one unit of work is said to have been ordrawn untilit has been increased to four times ,N-ITED STATES PATENT OFFICE;

HIRAM STEVENS MAXIM, OF LONDON, ENG AND.

MANUFACTURE OFGUNS.

SPECIFICATION forming part of Letters Patent 510,376,990, dated January24, 1888.

Application filed October 4, i587. seiial No. 251,389. (No model.)Patented in England March 1887, No. 4,320. 7

Beit known that I, HIRAM STEVENS MAXIM, mechanical engineer, a citizenof the United States of America, and a resident of London,

provemeuts in the Manufacture of Guns, (for which I have obtained apatent in Great Britam, No. 4,320, hearing date March 22, 1887,)

My invention relates to the manufacture of steel'guns, and is designedto provide for increasing the strength of the same and the homogeneityof the metal of which they are composed.

Steel guns haveiu some instances been manue factured from solid castingsor ingots by forging the same to the required external shape tougheningthe same by heating them in a furnace, and when heated to the requiredtem perature plunging them in oil, and then finishing them. In themanufacture of agun in this manner the. requisite number of "unitsof'work are put into the steel by hammering or drawing, which isdisadvantageous, for the reasons hereinafter explained. Moreover, the

cess of tempering or-toughening the same. By the term units of work Imean the ambunt of hammering or other working to which the steel must besubjected in order to impart the desired toughnessand density thereto.For instance, if the ingot is hammered ordrawnuntil it has beenincreased to twice its original put into the metal. If the'ingot ishammered itslength, three units of work are said to have put into themetal. I I

An important object of my present invention of units of work into'themetal of which; the gun is composed without the necessityfor hammeringor drawing or changing the form of the ingot for this purpose.Iaecomplish this result by twisting the steel casting or ingot while hotand before the same is forged, bored, or otherwise worked. In thismanner, more over, I insure that the grain or fiber ofthel metal shallextend in the direction calculated to give the greatest strength to thegun-that ingot.

is to say, that the grain or fiber shall extend I cireumt'erentially orspirally around'the bore. k

I can thus produce'guns-of very great strength as compared with those inwhich the requisite number of units of work are put into the steel byhammering or drawing. I Moreover, the twisting of the casting or ingotinsures uniformity in the distribution of the carbonand increases thehomogeneity of the metal.

provide for imparting tothe guna molecular condition, such as that whichexistsin abuiltup gunthat is to say, for insuring that the innerportions of the gun shall be undericom pr'ession while the outerportions thereof are in a state of tension. For this purpose I firsttemper or toughen the gun in the ordinary manner, and then reheat thesame, and while it is still in the furnace I cool it fromthe in or otherterio'r by means of air, water, oil, suitablecooling medium. p

In making a gun according to my present 6o -Another object of my saidinvention is to invention I proceed as follows-that is to say; l

"I take a steel casting-0r ingot of the requisite dimensions, and twistthe same while hot by means of alathe or othersuitabl'e machine un-'tilthe desired number of units of work has been put into the steel. Thistwisting is preferabl y so effected that it does not lengthenthe Theiiigot inay then be bored to the required caliber, turned, and otherwisefinlengthen it before being bored, 7 q

I find it advantageous to subject the casting oringot thus twisted tothe further operations hereinafter described-that is to'say, I forge thesaid ingot to the required externalshape or configuration, and thenroughly bore the same and temper or toughen it by means of oil in theordinary manner, thecooling being ished; or it maybe hammered or drawnto effected from the outside as well-as'from the f inside of the gun.' Ithen heat the gun to a' and its exterior is subjected to heat Icool it.internally, using for this purpose a blast or current of cold air, orofair and steam, or of airhaving in suspension therein water in afinely-divided or atomized condition, or a blast or current of aircombined with aspray of oil,. or a stream of oil or of hotor cold water,the

redheat, and while'itis still in the furnace means employedbeing variedaccording to the nature or the desired hardness of the steel, the

dimensions of the gun, and other circumstances.

I then finish the gunin any convenient manner.

In some instances I repeat as often as may be required the operations oftempering or toughening the gun in the ordinary manner and of coolingthe 'gun internally while subjected to heat externally, as abovedescribed, for the purpose of improving the quality ofthe steel. 1

It is evident that by twisting the ingot, instead of hammering ordrawing the same, to put the desired number of units of work into themetal, the effect of any air-hole or other fault in the metal will bediminishedinstead of increased. For instance, assuming a fault such as aspot containing too much or too little carbon-to exist in the ingot, the.hammering or drawing would lengthen the said fault or draw it outlengthwise of the gun, thereby diminishing the resistance of the gun tointernal pressure, whereas by the twisting of the ingot the fault isdrawn out circumferentially, so that the strength of the gun to resistinternal pressure will be increased.

I can, if desired, take a hollow casting'and twist it, in the mannerabove described, until any desired number of units of work is put intothe steel, the said hollow casting being subsequently forged, ifnecessary, tempered or toughened, and finished, as above specified.

What I claim is- 1. The improvement in the manufacture of steel guns,which consists in twisting the steel casting or ingot to be used inmaking the gun, as and for the purpose set forth.

2. The improvement in the manufacture of steel guns, which consists intwisting the steel castingor ingot to be used in making the gun and thencooling it internally, as set forth,

. 3. The improvement in the process of making steel guns, which consistsin twisting the steel casting or ingot to be used in making the gun andthen heating and coolingitinternally.

4. The improvement in'the process of making steel guns, which consistsin twisting the steel cast-ing or ingot to be used in making the gun,boring the casting oringot when castsolid, and then cooling itinternally while its exterior is exposed to heat.

5. The improvement in the process of making steel guns, which consistsin twisting the steel casting or ingot to be used in making the gun,boring the same when cast solid, then tempering or toughening it in theordinary manner, and then reheating it and cooling it internally whileits exterior is exposed toheat, asset forth.

6. The improvement in the process of making steel guns, which consistsin twisting the steel casting or ingot to be used in making the gun,then forging the said casting or ingot to the desired shape orconfiguration,then roughly boring the same, and then heating it andcooling it internally while its exterior is ex posed to heat, as setforth.

7. Theimprovement in the process of making steel guns, which consists intwisting the steel casting or ingot to be used in making the gun, thenforging the said casting or ingot to the desired shape or configurationand roughly boring the same, then tempering or toughening it in theordinary manner, and then reheating it and cooling itinternally whileits exterior is exposed to heat.

In testimony whereof I have hercnnt o signed my name in the presence oftwo subscribing witnesses.

HIRAM STEVENS MAXIM.

\Vitnesses:

DAVID YOUNG, \VALTER MORRIS.

